Vehicle driver's cabs and similar control stations have been made to be of a variable height nature in the past, in two substantially different ways. One type commonly seen is the cab-over-engine type of truck cab, in which substantially the whole shell of the body may be tilted up in order to expose the engine and chassis for more convenient servicing. Most often with this sort of apparatus tilting up the cab disconnects many of the controls and at the least the vehicle cannot be operated while the cab is tilted up. This first type is not what the present invention is about.
The second kind of variable height vehicle cab is found most often on off-the-road vehicle, such as construction and mining machinery, where there is a need at some times for the machine to have a low profile, and a need at other times for the operator to be at a more elevated level so he or she has adequate visibility for the task at hand. With vehicles of this second sort it is essential that the vehicle be able to be driven or the machine to be otherwise operable in both modes, i.e. both while the cab is in its lower "low profile" mode and while the cab is in its upper "high visibility" mode. Often with vehicles of this latter sort, the cab may be raised or lowered to any intermediate position as well. The present invention primarily relates to this second sort of variable height vehicle cab.
The term "vehicle cab" is used generically herein to indicate not only the perch from which the vehicle is driven, i.e. where the "driver's seat" is located on a translatable, self-propelled machine, but also other operator work stations on equipment, such as the familiar, steering work station on the rear, towed unit of a "hook-and-ladder" fire truck; the bailing, binding, bagging or threshing or like work stations on agricultural implements; wheel houses on water craft such as river barges; drawbridge works-operating stations and the like.